There is known a particle beam treatment for irradiating a patient's cancer affected part with an ion beam of protons, heavy ions or the like as a radiation treatment for cancer. A particle beam therapy system needs to make highly accurate beam position adjustment to introduce the ion beam into the affected part, and takes a great deal of time for the adjustment and testing. Patent Documents 1 and 2 describe the adjustment and the testing of the particle beam therapy system.
If the need to update an existing system to a new system in the same site arises due to aging of the existing system, application of improvement following technological advancement, such a flow may be considered as to stop the system, replace the existing system with the new system, and treatment is started with the new system after testing the new system. However, it takes time to adjust and test the system at a time of update and a suspension period of treatment is prolonged. During that period, patients cannot get treatment, it is difficult to maintain installation and maintain employees, and other disadvantages occur. Considering that the system update is accompanied by disadvantages, it is desired to avoid a long suspension period of treatment.